CN102460270B - Light polarization modulator and there is the stereo projecting equipment of light polarization modulator - Google Patents

Abstract

A kind of polarization switch provides substantially desirable two condition polarization to switch by using polarization modulation wheel in the wavelength coverage of broadness, and described polarization modulation wheel has at least one retardation plate lamination of conversion polarization.In polarized systems, use described polarization modulation wheel to provide high flux polarization switch, and at the same time for each assembly of the polarisation based group for any selection provides continuous print, stable polarization substantially to work in large ranges of incidence angles when exporting.Described polarization modulation wheel is very suitable for three-dimensional polarization projection application.

Description

Light polarization modulator and there is the stereo projecting equipment of light polarization modulator

background

Technical field

Present disclosure generally relates to two condition (binary) light polarization modulator, and more specifically, relates to the application of two condition light polarization modulator for sequential stereo projection system.

Background technology

Sequential stereo projection system presents full frame left and right fluoroscopic image alternately to the eyes be applicable to.With regard to this point, they use the synchronous operation of the tripper of projector and certain form.Among benefit, the method makes it possible to the single projector 3D display realizing the inregister automatically providing two images.The element of shutter system may not be all stay spectators there, but the analyzer of certain form should be used in spectators there to distinguish coded image.Based in the system of polarization, cross polarization analyzer is placed on spectators there by the simplest method, and other elements of shutter are stayed projector place.Usually, the latter comprises the active polarization switch of input polarization device and certain form.Because only single copy is used for the element of analyzer upstream, so this has make cost and the minimized benefit of complexity.But it has strict requirement for the polarization dependence of any add ons be placed in shutter (such as, veil (screen)).

Exemplary display technique can realize switching (such as, <100 μ s) quickly, to make the complete time that there is image be separated.In many cases, further preferably such auxiliary shuttern, this auxiliary shuttern adapts to the limited switching time of 3D shutter device, thus crosstalk reduction (fractional transmission of error image).Digital light process (DLP) optical projection system is exactly such situation, and DLP optical projection system such as makes to carry out hidden liquid crystal (LC) polarization by the high speed of display, the shutter of high dynamic range and switches transformation.In principle, coded system can be any technology making to be applicable to every ocular delivery image.This can comprise any non-overlapped spectrum to, any cross polarization group, or even angle or position.At present, the system based on polarization is modal in digital camera.

Modal polarization switch utilizes high speed LC pattern.Although use such equipment in most of 3D digital camera platform, they but have some performance deficiencies.Specifically, for the system worked than (throw-ratio) with low projection (those systems such as under family/working environment), high-contrast is difficult to keep.In addition, LC equipment operating coordinates circular polarization most convenient, but there is the situation (such as, the market extremely responsive to glasses price, or the place that linear polarizer glasses are general, such as theme park) of preferred linear polarizer.In addition, due to the color attributes based on the retardation plate film used in circularly polarized system (retarder film), and current system is caused usually to suffer some unlatching state losses in efficiency.

Summary of the invention

Disclose light polarization modulator.According to one side, light polarization modulator can operate and carry out time-modulation to the linearly polarized light of injecting in light path.According to another aspect, light polarization modulator has the polarization wheel be positioned in linear polarization light path.Polarization wheel can have the first circular arc district and the second circular arc district, and at least one in the first circular arc district and the second circular arc district comprises retardation plate lamination light filter (retarder stack filter).According to another aspect, both the first circular arc district and the second circular arc district all comprise retardation plate lamination light filter.

According on the other hand, also disclose stereo projection system.According to this aspect, stereo projection system has projector sub-system and Polarization Modulation subsystem.Projected image time-modulation from projector sub-system can be orthogonal polarization state by light polarization modulator subsystem.Light polarization modulator subsystem has polarization wheel, and this polarization wheel has the first circular arc district and the second circular arc district.Both the first circular arc district and the second circular arc district all comprise retardation plate lamination light filter.

Accompanying drawing explanation

Illustrate embodiment by way of example in the accompanying drawings, in the accompanying drawings, similar label indicates similar parts, in the accompanying drawings:

Figure 1A to Fig. 1 C is the schematic diagram illustrating polarizer wheel (polarizer wheel);

Fig. 2 is the schematic diagram of the geometric configuration illustrating order wheel (sequential wheel) and projection hot spot (projected light patch);

Fig. 3 A is the sequential chart of the dutycycle illustrating conventional polarizer wheel;

Fig. 3 B is the schematic diagram of the geometric configuration illustrating order wheel and projection hot spot;

Fig. 4 be illustrate conventional polarizer wheel contrast ratio (contrast ratio) relative to the curve map of dutycycle (duty cycle);

Fig. 5 is that the contrast ratio of conventional polarizer wheel under worst case angle situation is relative to the curve map of dutycycle;

Fig. 6 is the sequential chart of the dutycycle illustrating conventional polarizer wheel;

Fig. 7 be about sectional type (segmented) linear polarizer wheel contrast ratio to the curve map of dutycycle;

Fig. 8 is the form of the characteristic value illustrated about commercially available three-dimensional 3D sectional type polarizer wheel system;

Fig. 9 is the schematic diagram of the optical projection system illustrated according to present disclosure;

Figure 10 is the schematic diagram of another optical projection system illustrated according to present disclosure;

Figure 11 is the schematic diagram of the exemplary light polarization modulator wheel according to present disclosure;

Figure 12 is to provide the form of the exemplary angle of 12 layers of retardation plate lamination according to present disclosure;

Figure 13 is the form of the six layers of pure achromatic rotator prior (pure achromatic rotator) illustrated according to present disclosure;

Figure 14 is the curve map of the transmission ullage (transmission leakage) of the six layers of achromatic rotator prior lamination illustrated according to present disclosure;

Figure 15 is the form of the solution according to present disclosure;

Figure 16 is the curve map of the transmission of the desirable analyzer illustrated according to present disclosure;

Figure 17 is the drawing of the ullage of crossed-polarizer (crossed polarizers) according to present disclosure; And

Figure 18 be to illustrate according to the parallel polarizer of present disclosure between the drawing of ullage of pure achromatic rotator prior.

Embodiment

The alternative of LC polarization switch utilizes electromechanical switch device to produce stereoeffect.A kind of usual manner done like this utilizes easy polarizer to take turns in the following manner, that is, by the half of the linear polarizer covering disk of arbitrary orientation, and cover second half of this dish with the linear polarizer of transmission cross polarization.This dish is affixed to servomotor, this servomotor be provided for making from projector field sequence image present the timing pip synchronous with light polarization modulator.Export as unpolarized with regard to projector, polarizer wheel does not produce intensity modulated at projector place.

Figure 1A, Figure 1B and Fig. 1 C is the schematic diagram illustrating conventional polarizer wheel 100,150 and 180.With reference to Figure 1A, show easy order polarizer (or single segmentation (single segment)) wheel 100.The half 102 of wheel transmission can have the light of the first polarization 112, and second half of wheel 104 transmission can have the light of the second polarization 114.Second polarization 114 is orthogonal with the first polarization 112.Wheel will attach to motor, and the rotation taken turns by with from the field sequence image of projector and light polarization modulator synchronous.

Analyzing glasses also will comprise the eyeglass with orhtogonal linear polarizaiton device.The simulation that driving-disc produces input polarization device rotates, and result produces the intensity modulated transmission of simulation at eyes place.

For single segmented wheel 100, the single orientation for every occurs by optimum contrast.At each semiperiod (half-cycle), between orthogonal orientation, existence is suddenlyd change, in the dark section (black segment) of wheel or the shutter of projector, may be used for the further deterioration avoiding contrast.The minimum angles scope that this covers (blanking) depends on the size of the hot spot on wheel.But contrast is usually poor when utilizing single segmented wheel, be to increase the time of covering for the mechanism improving contrast, but this with flux (throughput) for cost.Because when using single segmentation, all points all experience substantially the same instantaneous polarizer orientation, so expection contrast ratio is consistent, precondition is the angular range being enough to cross over hot spot (spoke (the spoke)) time of covering.

Fig. 2 illustrates to be had that width is L, the schematic diagram of the geometric configuration of order wheel 200 that highly irradiates for the hot spot of H.Wheel 200 has radius R and the angle φ by the angular definitions between light 202 and light 204.The center 203 that the center 201 of light 202 trailing wheel extends through hot spot arrives the edge of wheel 200.The center 201 of light 204 trailing wheel extends through the lower corner 205 of hot spot.Suppose that the ratio that 3D contrast is transmitted according to time averaging unlatching state (on-state) transmission and pass closed state (off-state) provides.It is uniform (for DLP system, this is never entirely accurate) in time that this calculating hypothesis source is irradiated.In addition, it should be noted that the modulation of tripper can form pseudomorphism in sequential GTG projector in this, this modulation should be made to minimize.

Fig. 3 A is the diagram of the sequential 310,320,330,340 of easy the to be single segmented polarizer device wheel 350 illustrated for Fig. 3 B.Single segmented polarizer device wheel 350 has two polarizations half part (polarizing half) 352,354.First polarization half part 352 transmission can be in the light of the first polarization 362.Second polarization half part 354 transmission is in the light of second polarization 364 orthogonal with the first polarization 362.Polarizer wheel 350 can be irradiated by hot spot 370.

Get back to Fig. 3 A, top sequential chart 310 illustrates the polarizer transmission orientation 315 in the frame of analyzer.Second sequential chart 320 illustrates the optical delivery 325 be associated.3rd sequential chart 330 illustrates the switching 335 of projector field.Last sequential chart 340 illustrates effectively transmission 345.

Contrast ratio can calculate from the integration of following characterization time average transmission:

${\stackrel{\&OverBar;}{T}}_{\mathrm{OFF}}=\frac{2}{\mathrm{\&tau;}}\underset{0}{\overset{\mathrm{\&tau;}/2}{\&Integral;}}{\sin }^2\left({\mathrm{\&omega;}}_{0}t\right)\mathrm{dt}$

${\stackrel{\&OverBar;}{T}}_{\mathrm{ON}}=\frac{2}{\mathrm{\&tau;}}\underset{0}{\overset{\mathrm{\&tau;}/2}{\&Integral;}}{\cos }^2\left({\mathrm{\&omega;}}_{0}t\right)\mathrm{dt}$

Wherein, τ is a duration, and ω ₀be angular frequency, this integration obtains contrast ratio

$\mathrm{CR}=\left[\frac{1+\left(\frac{\sin \mathrm{\&eta;}}{\mathrm{\&eta;}}\right)}{1-\left(\frac{\sin \mathrm{\&eta;}}{\mathrm{\&eta;}}\right)}\right]$

Wherein, η=ω ₀τ/π is dutycycle.

Fig. 4 is such curve map 402, and contrast ratio is characterized by the function 402 of the dutycycle of simple single segmented line polarizer wheel by this curve map.As illustrated by line 402, significantly reduce along with dutycycle increases contrast ratio.Therefore, for single segmented line polarizer wheel, acceptable contrast is difficult to realize in any rational dutycycle.

Getting back to Figure 1B, showing by using gradient orientation (gradientorientation) polarizer 150 to make the minimized method of the modulation in polarizer orientation.In the half 152 of dish, polarizer transmission axle is radial trend, and at second half of dish on 154, polarizer transmission axle is position angle trend.Because such equipment makes incompatible with the polarizer based on net (web-based) substantially, so it is current and impracticable, although it is the alternative interested of single staging device (shown in Figure 1A and Fig. 3 B).Gradient orientation polarizer 150 can provide the contrast limited along the polarization efficiency of single radial direction by polarizer.Due to the limited size of hot spot, contrast reduces along with the angle deviating with this orientation.

For such a system, with regard to the spatial coherence in contrast, dish/glasses and projector are usually configured to the heart in the picture and provide the highest possible contrast and performance reduces about vertical axis.

Get back to now Fig. 2 (in fig. 2, width is L, highly for the hot spot of H is incident on wheel by the clear aperature (clear aperture) that radius is R), minimum shield angle φ provides according to following equation:

$\tan \mathrm{\&phi;}=\frac{L/2}{\sqrt{R^2-{(L/2)}^2}-H}$

Suppose to be arranged on below projector by wheel hub (hub) as shown, then minimum shield angle φ determines according to the inferior horn 205 of hot spot.The maximum contrast ratio of these worst case positions is provided by square inverse of above equation or following equation:

CR＝cot ²φ。

Suppose rough length breadth ratio L/H ≈ 2, then wheel hub can be navigated to the left side or the right of projector, therefore, dutycycle be maximized.But this can cause the left or right in optic response asymmetric.

Fig. 5 be radial polarisation device wheel bight or worst case angle in contrast ratio 502 as the curve map 500 of the function of dutycycle, provided by following equation in the angle of described bight or worst case:

$\mathrm{\&eta;}=1-\frac{2\mathrm{\&phi;}}{\mathrm{\&pi;}}.$

Although this performance than single segmented wheel (Fig. 1 and Fig. 3 B shown in) is better, though 95% very high dutycycle, the maximum-contrast in described bight is also only above 100: 1.In the more real dutycycle of 90%, contrast ratio is approximately 50: 1.As mentioned above, real gradient orientation polarizer commercially can't buy at present.

Referring now to Fig. 1 C, approaching of real gradient orientation polarizer 180 can realize by the section 182 of individual for integer (N) suitable orientation to be laminated on dish.Temporal correlation is incorporated into polarizer orientation by again, in this case, after resetting suddenly, and the gradual change (ramp) in each experience polarizer orientation of hot spot.Owing to not having such modulation for drift angle (bias angle), thus gradient orientation polarizer shows the upper limit of performance.But as front, spatial coherence is introduced contrast ratio by drift angle.

When every (per field) uses several sections 182, contrast can be estimated by the time average during the one-period of serrate polarizer orientation waveform (again supposing it is stable source in time).The actual phase of serrate profile depends on the orientation relative to specific shot point.

Fig. 6 is the sequential chart of the optic response 604,606,608 at three the some places illustrated on polarizer orientation waveform 602 and hot spot.Optic response 604 is relevant to central point, and optic response 606,608 (difference) is relevant with right point to left point.These points are optional, and the one-period of serrate orientation waveform of being separated by, be therefore homophase.Optical response plot illustrates drift angle relative to opening state and the effect of pass closed state curve.Here, select central point with have characterize maximum-contrast, the response 604 of substantial symmetry, and left/right point has the minimum/maximum offset in an opposite direction by drift angle.Although the specific time sequence changing (or covering interval) relative to the field of polarizer modulation can have some to affect on result, contrast is estimated to be provided by the integration during the single cycle quite accurately:

${\stackrel{\&OverBar;}{T}}_{\mathrm{OFF}}=\frac{1}{\mathrm{\&tau;}}\underset{-\mathrm{\&tau;}/2}{\overset{\mathrm{\&tau;}/2}{\&Integral;}}{\sin }^2({\mathrm{\&omega;}}_{0}t+\mathrm{\&phi;})\mathrm{dt}$

${\stackrel{\&OverBar;}{T}}_{\mathrm{ON}}=\frac{1}{\mathrm{\&tau;}}\underset{-\mathrm{\&tau;}/2}{\overset{\mathrm{\&tau;}/2}{\&Integral;}}{\cos }^2({\mathrm{\&omega;}}_{0}t+\mathrm{\&phi;})\mathrm{dt}$

Wherein as front,

$\mathrm{\&phi;}=\frac{\mathrm{\&pi;}}{2}(1-\mathrm{\&eta;})$

η is the dutycycle of each, and

$\mathrm{\&tau;}=\frac{\mathrm{\&pi;}}{N{\mathrm{\&omega;}}_0}$

Wherein, every exists N number of polarizer section.More than use contrast ratio is given as:

$\mathrm{CR}=\left[\frac{1+\cos 2\mathrm{\&phi;}\left(\frac{\sin \frac{\mathrm{\&pi;}}{N}}{\frac{\mathrm{\&pi;}}{N}}\right)}{1-\cos 2\mathrm{\&phi;}\left(\frac{\sin \frac{\mathrm{\&pi;}}{N}}{\frac{\mathrm{\&pi;}}{N}}\right)}\right].$

Fig. 7 is that the contrast ratio of sectional type linear polarization wheel (as shown in Figure 1 C) for several N value is to the curve map 700 of dutycycle.Quantity along with section becomes large, and reduce polarizer modulation range, performance is improved gradually, finally converges to gradient orientation polarizer situation (N → ∞).Consider the quantity of dutycycle, section and the actual Consideration of polarization efficiency, from contrast, crosstalk viewpoint, this shows that the linear polarizer system using sectional type wheel is not feasible premium quality product.Above embodiment shows, the contrast for linear polarizer system exists the restriction of being forced by the finite size size of the hot spot on wheel.

As some the alleviation modes realizing angle sensitivity, a solution changes polarisation based group (polarization basis set).In the preferred case, circular polarization is initiated and is constant in rotary course (removing inessential phase place).Most realistic when, circular polarization uses strained polymer retardation films to produce, and described strained polymer retardation films uses pressure adhesive relative to linear polarizer one-tenth ± π/4 lamination.This solution increases system cost, specifically because each eyeglass will containing quarter-wave film.The selection that cost is minimum is at single visible wavelength λ ₀zeroth order (zero-order) retardation plate of ideal delay is provided.At other wavelength, postpone to depart from, and will the loss of contrast be associated be there is.

The Jones matrix of this situation is provided by following equation:

t＝P(π/2)W(-π/4，Γ)R(φ)W(π/4，Γ)P(0)

Wherein, P characterizes the linear polarizer in indicated orientation, and W characterizes the linear delay sheet with the indicating position postponed for Γ, and R characterizes anglec of rotation φ.Calculate above equation power delivery (power transmission) is given as:

T _OFF＝|t _xy| ²＝sin ²φsin ²δ

Wherein, δ is delay error, or

$\mathrm{\&Gamma;}=\frac{\mathrm{\&pi;}}{2}+\mathrm{\&delta;}.$

As expected, for all φ, leakage loss is transmitted as zero, and precondition is polarization state is circular.Available accurate achromatism (quasi-achromatic) retardation films (such as, Teijin WB series improves PC retardation plate) realizing high stability length of delay, but zeroth order retardation plate is relatively cheap, and be easy to buy.

The delay error of zeroth order retardation plate is provided by following equation:

$\mathrm{\&delta;}\left(\mathrm{\&lambda;}\right)=\frac{\mathrm{\&pi;}}{2}[\frac{\mathrm{\&Delta;n}\left(\mathrm{\&lambda;}\right)}{\mathrm{\&Delta;n}\left({\mathrm{\&lambda;}}_0\right)}\frac{{\mathrm{\&lambda;}}_0}{\mathrm{\&lambda;}}-1]$

Wherein, λ ₀be design wavelength, this design wavelength is usually in the cyan/green portion of visible part.Usually according to realizing the highest suitable optical contrast ratio (requiring higher delay) and providing this value of compromise selection between acceptable blue performance (requiring lower delay).Dispersion or birefringent wavelength dependence or Δ n is also comprised in this calculating.Dispersity due to polycarbonate is moderate and commonly use in the industry at present, so this is the factor that be considered.

Because delay continuous item and orientation have nothing to do, so contrast calculates with embodiment above proportional, provide result:

CR(circular)＝G·CR(linear)

The instruction of this result has contrast gain factor G based on the system of circuit polarizer relative to the system based on linear polarizer.Actual gain can be provided by following equation:

$G=\frac{\underset{\mathrm{\&Delta;\&lambda;}}{\&Integral;}\stackrel{\&OverBar;}{y}\left(\mathrm{\&lambda;}\right){\cos }^2\left[\mathrm{\&delta;}\left(\mathrm{\&lambda;}\right)\right]\mathrm{d\&lambda;}}{\underset{\mathrm{\&Delta;\&lambda;}}{\&Integral;}\stackrel{\&OverBar;}{y}{\sin }^2\left[\mathrm{\&delta;}\left(\mathrm{\&lambda;}\right)\right]\mathrm{d\&lambda;}}$

Wherein, Δ λ is visible spectrum, and it is photopic response curve.By using the centre wavelength of polycarbonate dispersion and 516nm, gain factor is approximately G=26.This gain factor by be applicable in the above embodiment provided any one, have appreciable impact to performance significantly.Turn back to easy single segmented polarizer device wheel (as shown in Figure 1 and shown in Figure 3 B), the contrast ratio of the dutycycle maximum possible 74% is lower than 50: 1.Even if so use zeroth order circular polarization system, single segmented polarizer device wheel also cannot realize required performance level, as in the cinema system that LC switches use.

Fig. 8 is the form 800 of the eigenwert that commercially available three-dimensional 3D sectional type polarizer wheel system is shown.The size of hot spot is based on typical (being never worst case) structure.Actual spot size depends on that emergent pupil (exit pupil) is to the projection ratio of wheel and distance (it depends on the physical extent of eyeglass/housing and the actual degree of approach of wheel).

In fact, the picture centre contrast number of degrees are situations of optimal cases.Consider polarization efficiency and other depolarized factors of projector and glasses line polarizer, this number is in fact much lower.Only consider typical polarization efficiency, can easily make the contrast of picture centre reduce by half.

the shortcoming of routine techniques

Therefore, need such polarization switch, this polarization switch provides almost desirable two condition polarization to switch in wide in range wavelength coverage.The high flux polarization switch that further needs are such, the structure of this polarization switch is simple, and works in large ranges of incidence angles.Also need such polarization switch, this polarization switch realizes these performance objectives while with the work of linear polarization mode, and described linear polarization is modal is produced by current mass-produced cheap assembly.Also need such two condition polarization switch, this two condition polarization switch provides continuous print, stably polarization to export for any selected (particularly, linear) polarisation based group at every field interval.In addition, need such modulating system, this modulating system can carry out two condition switching by simple substitute/being added between any cross polarization state combination of passive block.

polarization Modulation system

Embodiment disclosed in present disclosure meets above-mentioned needs, and simulation swiveling wheel can be used to realize.Except other application, the Polarization Control wheel of present disclosure also can be used for three-dimensional 3D system, switchable spectral filter, for the binary picture shift component that shows (such as, jitter modulation process (wobulation)) or for the binary picture shift component (such as, anti-aliasing) that catches and polarization metrology.Embodiment disclosed herein can use together with the polarization-sensitive element in any downstream, and to provide the two condition of certain optical characteristics to switch, no matter it is polarization, position, direction, wavelength, intensity, or complex amplitude.

As previously mentioned, to the polarizing filter wheel of the light beam work of large space and spectral range produce simulated time modulation, position correlated polarizations or both certain combination.This is specially adapted to linear polarization, and in linear polarization, for the dutycycle of any reality, contrast ratio is generally all poor.Present disclosure overcomes this problem by the rotation substantially eliminating polarizer.Polarizer is restricted to the structure of the polarization degree improving incident non-polarized light in this article.According to present disclosure, input polarization element is on the fixed position of the upstream of filter wheel.

Fig. 9 is the schematic diagram illustrating the optical projection system 900 that can produce two condition Polarization Modulation.

In embodiments, optical projection system 900 comprises projection engine 902, synchronizing linkage 904, and synchronizing linkage 904 drive the motor 910 be connected with Polarization Modulation assembly 912.Optical projection system 900 can also comprise projecting lens 906, in the light path of projecting lens 906 between projection engine 902 and Polarization Modulation assembly 912.

System 900 can comprise optional input polarization device 908.Input polarization device 908 is for making the nonpolarized light polarization exported when projection engine exports nonpolarized light (such as, based on projection engine or the DLP projection engine of micro mirror).Input polarization device 908 can be selected to remove the polarisation of light of polarization for the projection engine (such as LCoS projection engine) based on polarization.Polarization Modulation assembly 912 is positioned in after projecting lens 906 and (if comprise optional input polarization device 908, is then positioned in after projecting lens 906 and input polarization device 908).Optional input polarization device 908 is linear polarizers.In some embodiments, system 900 can comprise passive polarization conversion assembly 914 alternatively, passive polarization conversion assembly 914 is positioned in after Polarization Modulation assembly 912 (such as, can operate quarter-wave plate linearly polarized light being transformed to circularly polarized light).

The light of output can project on screen 924 by optical projection system 900.Then system 900 user or spectators 922 can use polarization analyzing glasses 920 to watch projected image.Fig. 9 illustrates the assembly of optical projection system 900, screen 924 and wears the user/spectators 922 of analyzing glasses 922.Although Fig. 9 illustrates that spectators or user 922 are in line with screen 924 and optical projection system 900, and it will be appreciated by those skilled in the art that, should describe be for illustrating system, screen and user, but projected image be actually according to standard front projection arrange be projected on screen 924.Actual user/spectators 922 will be positioned in the side identical with optical projection system 920 of screen 924, and will watch reflected image from screen 924.In embodiments, screen 924 can be protect projection screen to the front (such as, as the U.S. Patent application No.12/361 of the people such as Coleman, the screen of instructing in 532 or screen, be incorporated to this U.S. Patent application herein by quoting).

Figure 10 is the schematic diagram illustrating the optical projection system 1000 that can produce two condition Polarization Modulation.Except projecting lens 1018 be positioned at Polarization Modulation assembly 1012 below except, the principle of optical projection system 1000 and the optical projection system described in Fig. 9 900 similar.

In this exemplary embodiment, optical projection system 1000 comprises projection engine 1002, synchronizing linkage 1004, and synchronization structure 1004 drives the motor 1010 be connected with Polarization Modulation assembly 1012.Projection engine 1002 and Polarization Modulation assembly 1012 are contained in projector 1016, and projector 1016 has the projecting lens 1018 be positioned in Polarization Modulation assembly 1012 light path below.In this embodiment, system 1000 can comprise optional input polarization device 1008.Polarization Modulation assembly 1012 is positioned in after projection engine 1002 and (if comprise optional input polarization device 1008, is then positioned in after projection engine 1002 and input polarization device 1008).Optional input polarization device 1008 is linear polarizers.In some embodiments, system 1000 can comprise alternatively and is positioned in Polarization Modulation assembly 1012 passive polarization conversion assembly 1014 below.In some embodiments, Polarization Modulation assembly 1012 can be rotational latency sheet lamination filter wheel.

The light of output can project on screen 1024 by optical projection system 1000.Then system 1000 user or spectators 1022 can use polarization analyzing glasses 1020 to watch projected image.Figure 10 illustrates the assembly of optical projection system 1000, screen 1024 and wears the user/spectators 1022 of analyzing glasses 1022.Although Figure 10 illustrates that spectators or user 1022 are in line with screen 1024 and optical projection system 1000, and it will be appreciated by those skilled in the art that, should describe be for illustrating system, screen and user, but projected image be actually according to standard front projection arrange project on screen 1024.Actual user/spectators 1022 will be positioned in the side identical with optical projection system 1020 of screen 1024, and will watch reflected image from screen 1024.In embodiments, screen 1024 can be protect projection screen to the front (such as, as the U.S. Patent application No.12/361 of the people such as Coleman, the screen of instructing in 532 or screen, be incorporated to this U.S. Patent application herein by quoting).

Figure 11 is the schematic diagram of the embodiment illustrating polarization wheel 1100.Polarization wheel 1100 has the first circular arc district 1102 and the second circular arc district 1104.In embodiments, at least one in the first circular arc district 1102 and the second circular arc district 1104 is retardation plate lamination light filter (represented by 1110).Wheel 1100 rotates around turning axle 1106, and is positioned in linear polarization light path, to make when linearly polarized light is through this linearly polarized light rotation predetermined angular during one or two in the first circular arc district 1102 and the second circular arc district 1104.

In another embodiment, both the first circular arc district 1102 and the second circular arc district 1104 are all retardation plate lamination light filters.First retardation plate lamination light filter 1102 is θ degree polarization state spinners, and the second retardation plate lamination light filter 1104 is (θ-90) degree polarization state spinners.Such as, the first retardation plate lamination light filter 1102 can be+45 degree polarization state spinners, and the second retardation plate lamination light filter 1104 can be-45 degree polarization state spinners.In embodiments, both the first retardation plate lamination light filter 1102 and the second retardation plate lamination light filter 1104 are all finite impulse response (FIR) (FIR) light filters, and can produce the light pulse of at least N+1 spatial deviation in response to linearly polarized light Puled input.

Polarization wheel 1100 can transmitted light, to make the polarisation of light state left in the light path in the first circular arc district 1002 orthogonal with the polarisation of light state in the light path leaving the second circular arc district 1004.Such as, in embodiments, input polarization polarisation of light state can be converted 90 degree by the first circular arc district 1102, and the second circular arc district 1104 can not convert input polarization polarisation of light state.

In embodiments, the first circular arc district 1102 and the second circular arc district 1104 are made up of dispersionless retardation plate material (such as, cyclic olefine copolymer, polycarbonate etc.) substantially, and can comprise antireflective coating.

As mentioned above, polarization wheel 1100 can be used as Polarization Modulation equipment.In the embodiment of Polarization Modulation equipment, the quarter-wave retardation plate that polarization wheel 1100 can also be combined in polarization wheel light path below uses.Quarter-wave retardation plate may be oriented and becomes+45 degree relative to the polarization state from the first circular arc district 1102, and is oriented relative to polarization state one-tenth-45 degree from the second circular arc district 1104.

Polarization wheel comprises unitary polarization conversion device, with regard to this point, can convert polarization state.According to unitary transformation, input cross polarization will still keep like this after by described structure.

When given fixing input line polarizer, can to output polarization carry out two condition modulation, precondition be polarization conversion device and they independently realize suitable function relative to the orientation of analyzer.Consider the simple scenario of polarization wheel after linear polarizer, described polarization wheel is used for transmission at the immovable polarization of a kind of state, and is cross polarization by the State Transferring replaced.For the first state, wheel can be isotropic, with the unaltered light beam of transmission-polarizing.For the second state, second should be converted into the orhtogonal linear polarizaiton irrelevant with taking turns orientation.

As previously mentioned, because circular polarization is constant when rotated inherently, so they are special circumstances.Therefore circular state is utilize the similar key rotating acquisition two condition and switch, just as aforementioned circuit polarizer wheel embodiment.But, in this particular case, all use achromatism circuit polarizer to obtain ideal system level performance at both projector and analyzer place.Polarization conversion device can have round eigen polarization, so during rotation keep cross polarization to mean the phase differential kept between orthogonal circular polarizations state.This means that inverting element should have almost nil linear delay, or be equivalent to there is optical activity.

(such as, as found in quartz) optical activity is defined as the character of round eigen polarization in this article.Eigen polarization be defined as one group respectively by anisotropic structure with the orthogonal polarisation state of constant polarisation transfer, the phase factor of these orthogonal polarisation state is different.Mathematically, these are the polarization states making Jones matrix diagonalization.In fact, except base vector (basis vector) is circular instead of except straight line, optical activity material is identical with the effect of linear delay sheet.When this phase delay is half-wave, input line polarization is converted into orthogonal polarisation state usually.This is because in optical activity medium, the projection of the linear state in any orientation always causes the circular state of same-amplitude.Consider the situation of harmless medium, in harmless medium, polarisation transformation almost preserves power (such as, not having dichroism).In this case, the phase delay determination anglec of rotation, with regard to this point, keeps half-wave retardation to guarantee that orthogonal straight lines state is transmitted.But ideal performance comes across the optical activity medium keeping the half-wave retardation had nothing to do with wavelength.Such achromatism optical activity composition is non-existent in natural world.

Present disclosure relates to the design of synthesis achromatism optical activity element, making and system-level use.As mentioned above, the structure of present disclosure utilizes linear delay sheet lamination as the structure block producing these character, and except other structures, these build block and are incorporated in the wheel of simulation, switches to produce two condition polarization.

A kind of design consideration is that optical activity retardation plate rhythmo structure should have zero clean linear delay.In multilayer retardation plate lamination, this is often called as composite delay (compound retardation).If stock only has linear delay, while this can be considered to be in the linear composite delay of suppression, build the utilization the optical activity of regulation from the complex effect of the element of multiple suitable orientation.A kind of such method is that retardation plate rhythmo structure is designed to two unit; A half (on each wavelength) with required optical activity, this half optical activity has arbitrary compounded linear and postpones, and another has identical optical activity, but this optical activity has relative (or intersection), and compounded linear postpones.When this two unit pairings, linear delay is almost eliminated, and optical activity is double simultaneously.This has the benefit of the deterministic design method only considered based on power delivery.Such retardation plate lamination can use network synthetic technology (if the people such as Robinson are at " Polarization Engineering for LCD Projection (the polarization engineering for LCD projection) " the 6th chapter in conjunction with conventional finite impulse response (FIR) (FIR) method for designing, described in Wiley & Sons (2004), be incorporated to herein by quoting) design.

Can design such retardation plate lamination, these retardation plate laminations are by producing required polarization rotation for inputting the zero/specific power applying to project along any orientation axes by force.For being selected to realize the film of the specific quantity of designing requirement, advantageously for the spectral bandwidth of maximum possible, spectrum secondary lobe is forced to remain lower than prescribed level (such as, < 0.1%).This guarantees that the high-level efficiency of retardation plate material uses, and when spectral coverage exceedes required spectral coverage, usually preferably reduces the quantity postponing lamella.As in any FIR design, for the specific number of plies, between sidelobe level and spectral coverage, there is basic balance.The half-wave wavelength that the spectral response of the lamination (in domain space) between parallel/crossed-polarizer postpones about basement membrane is symmetrical, so as front, this trends towards in visible cyan/green portion.In the design making film minimum number, centre wavelength is selected to provide the balance between pale blue and dark red ullage usually.

Based on more design method, the rotation of half lamination generation ± π/4, again has the arbitrary compounded linear that exports and postpones.The lamination that sense of rotation is identical, composite delay intersects can use identical stack-design to be formed, but rank are contrary with angle symbol.When catoptron is connected on after retardation plate lamination, there is similar situation.After reflection, retardation plate is by the contact of contrary rank, but effectively, angle is not changed.In this case the polarisation transformation of gained is based on the delay of rotation and the double of elimination.So by making the sign inversion of angle, produce a contrary effect.

Figure 12 is to provide the form 1200 of the angle of 12 layers of retardation plate lamination, and these 12 layers of retardation plate laminations produce the rotation of pure achromatic pi/2 substantially, and inverse rank reflection symmetry is followed in this rotation.Note, this symmetry is adequate condition for the polarisation transformation needed for realizing, but is not necessary condition.But searching algorithm can identify the stack-design not following inverse rank reflection symmetry with required effect similarly.Easy confirmation, the polarization state after layer 6 is the orthoscopic of π/4 orientation, but lamination has substantially by the linear composite delay of a rear lamination elimination.This design achromatism fully, to cross over whole visible spectrum (400-700nm) based on the dispersion of polycarbonate.

Spectral range and the film quantity height correlation of achromatism effect can be had.For being enough to, in 430-670nm band, there is the performance of near ideal and the optical projection system that reduces gradually of this extraneous tolerable performance, the number of plies can be reduced.And, if the retardation plate material (such as cyclic olefine copolymer (COC)) that near colorless falls apart is as the alternative of polycarbonate, then can reduce the number of plies further.

Figure 13 is the form 1300 that the six layers of pure achromatic rotator prior design being enough to be used in most of projection application are shown.

Figure 14 is the curve map 1400 of the transmission ullage illustrating the six layers of achromatic rotator prior lamination rotated between parallel polarizer.It illustrates the spectral response of the lamination of Figure 13, and this lamination uses the character of cyclic olefine copolymer (COC) the half-wave retardation sheet centered by 516nm.Curve map 1400 illustrates that transmission ullage is to wavelength when lamination to be placed between parallel polarizer and to rotate with the increment of π/12.Just as single retardation plate, the transmission response of any retardation plate lamination about ± π/4 are symmetrical.If make lamination rotate this angle, then can follow the tracks of the gamut of transmission curve.Figure 14 also illustrates for any lamination orientation, the contrast ratio being in the linear polarization of pi/2 rotation status in the spectral range of 416nm to 670nm more than 1000: 1.Ignore projector source characteristic, average suitable light ullage is provided by following equation:

${\stackrel{\&OverBar;}{L}}_{\mathrm{OFF}}=\frac{4}{\mathrm{\&pi;\&Delta;\&lambda;}}\underset{0}{\overset{\mathrm{\&pi;}/4}{\&Integral;}}\underset{\mathrm{\&Delta;\&lambda;}}{\&Integral;}\stackrel{\&OverBar;}{y}\left(\mathrm{\&lambda;}\right)T_P(\mathrm{\&lambda;},\mathrm{\&theta;})\mathrm{d\&lambda;d\&theta;}$

Wherein, T _p(λ, θ) is power delivery between parallel polarizer, that be oriented the achromatic rotator prior lamination relative to the design angled θ in orientation.Thered is provided by the isotropic segments of taking turns owing to opening state, so be reasonably desirable achromatism response (this supposes flat-top source (flat-top source) again) supposing not have azimuthal sensitivity be that total lumen exports:

${\stackrel{\&OverBar;}{L}}_{\mathrm{ON}}=\underset{\mathrm{\&Delta;\&lambda;}}{\&Integral;}\stackrel{\&OverBar;}{y}\left(\mathrm{\&lambda;}\right)\mathrm{d\&lambda;}.$

For the embodiment of Figure 13 and Figure 14, these give more than 20, the mean comparisons of 000: 1 leads so other aspects substantially by system limit by system-level performance on axle.In this rank, contrast can also be subject to the restriction of the polarization efficiency of projector and glasses line polarizer.High-performance linear polarizer can realize 4,000: 1 contrast, but only in very limited ranges of incidence angles.

For make a kind of method of wheel be use pressure adhesive (PSA) by retardation plate laminate to dish half on low birefringence glass/acrylic acid substrate.Which results in serious wheel equilibrium problem, so balance weight body or other isotropic substrate can be laminated to second half.Sub zero treatment can be used antireflection (AR) coating to be applied directly to lamination and wheel substrate.A kind of misgivings are that the flatness of retardation plate lamination may not obtain acceptable picture quality with this layout.

Method for there is the wheel of high optical quality can be arranged by interlayer (sandwich) and be realized.This can be realized by bonding coat between two optical qualities, low-birefringence antireflection coated substrate.The half of retardation plate lamination covering disk, the isotropy distance piece of matching thickness covers second half.These sheets utilize bonding agent that is water white, targets match (such as, thermosetting or uv solidification) to fix and be pressed together.When use has cyclic olefine copolymer (COC) of low stress optical coefficient, relatively hard (such as, acrylic acid) UV curing adhesive is permitted for assembling, thus obtains the larger assembly of rigidity.Typical bondline thickness in tens micrometer ranges, so be of value to very closely matching thickness.And the quality of glass spacer is different from retardation plate lamination, this still can cause some to take turns the challenge of balance aspect.

Replacement method is the both sides retardation plate lamination with the equal and contrary anglec of rotation being placed on wheel.This substantially eliminates the needs for distance piece, and for providing the specification of balance for the Polarization Control of often kind of state.Reduce by half owing to rotating, so the number of plies can also be reduced while maintenance overall contrast performance.

Method for designing above can be generalized to any anglec of rotation.About the method for designing that 90 ° of spinners are discussed before consideration.Whole relation between angle in each lamination is:

[α ₁，α ₂...α _N][-α _N...-α ₂...-α ₁]

Wherein, each lamination produces the required half rotated.This angle arranges the reflection symmetry had about 0.If the anglec of rotation is θ by overview, according to the pass of present disclosure be then:

[α ₁，α ₂...α _N][-(α _N+π/2-θ)...-(α ₂+π/2-θ)，-(α ₂+π/2-θ)]

This relation has the reflection symmetry about angle (θ/2-π/4).

Therefore, in embodiments, the method for the retardation plate lamination for being designed for polarization modulation wheel is disclosed.First, the synthesis anglec of rotation needed for selection, this angle θ characterizes.Then, suppose the input polarization along 0, the retardation plate lamination producing the power delivery of (being almost) zero in angle (θ+π)/2 can be designed.Then, can the second lamination of the above equation of design consideration.

Figure 15 is the form 1500 of a solution using said method.In the figure, ± 45 ° of achromatic rotator prior laminations are used for switching between orhtogonal linear polarizaiton.

Figure 16 illustrates the curve map 1600 using the transmission of the desirable analyzer of six layers of achromatism+45 ° of spinner laminations at-45 °.Curve map 1600 illustrates the light leak amount of the orthogonal analyzer desirable when retardation plate lamination rotates 45 ° from design angle.This illustrates and is greater than 1,000: 1 for any orientation contrast on most of visible spectrum.And adopt the suitable optical contrast ratio in flat-top source from 22,000: 1 (at design angle) changes to 34, the maximal value (when rotation 45 °) of 500: 1.So again, although system contrast can be dominated by other leakage loss sources, it should be noted that modulator can be left in the basket to the contribution of result.

In order to modulate between orthogonal linear state, contrary angle symbol construction second lamination can be utilized as shown in Figure 13.This has the effect changing polarization rotation symbol, but spectral results is substantially the same.As implied above, by using the input polarization device of the transmission had along transverse axis, wheel will switch between+45 ° and-45 ° of linear polarizations with high precision.By using the glasses with same orientation, high-contrast shutter can be realized.

This embodiment places arbitrarily input polarization device along specific direction.In embodiments, can be the orientation that the two kinds of polarization states leaving wheel correspond to the linear polarizer in glasses for a requirement of shutter.

Present disclosure can realize the three-dimensional 3D system based on high-contrast linear polarizer.But such system postulation analyzer is suitable in the reference frame identical with input polarization.In fact contrast can be rotated by geometry or head inclination and reducing fast.As previously mentioned, (because head inclination causes) can be eliminated by initiation and analyzing circular polarization about the susceptibility of the rotation of optical axis.With regard to present disclosure, the system based on circuit polarizer is possible.Generally, allow to realize circular polarization by quarter-wave retardation plate being placed on the linear polarization one-tenth ± 45 ° be orientated relative to leaving wheel after wheel and by this quarter-wave retardation plate.When directed analyzer as before, in each eyeglass, this is attended by the quarter-wave retardation plate of intersection.Note, because quarter-wave retardation plate disappears in unlatching state, so this layout can realize achromatism open state.Again, if at projector place with use achromatism quarter-wave retardation plate in glasses, then head inclination is utilized to there is the deterioration of insignificant contrast.

Under short throwing situation, three-dimensional 3D system can have the contrast that the visual field by light polarization modulator limits.In this case, contrast is determined by closing closed state ullage, and in eyes, described pass closed state ullage is given by the isotropic segments between crossed-polarizer, and in another eyes, described pass closed state ullage is given by the achromatic rotator prior between parallel polarizer.Suppose wheel be isotropic in this state, then the former ullage pass through ± position angle, π/4 in crossed-polarizer axle geometry rotate determine.Because polarization projection is along proper direction, thus contrast 0, pi/2 keeps near ideal in position angle.

Figure 17 is the polar plot 1700 of the lumen ullage of the crossed-polarizer when hypothesis 100 lumen inputs.For the maximum incident angle in air 40 degree, this polar plot of crossed-polarizer is shown.In another eyes, contrast is by being determined by the angle sensitivity of the retardation plate film forming lamination.Because polarizer is parallel, so there is insignificant geometry leakage loss effect.

Figure 18 be to illustrate for the parallel polarizer of 100 lumens inputs between the polar plot 1800 of ullage of pure achromatic rotator prior.When lamination is made up of uniaxial film, polar plot as shown.

Crossed-polarizer situation obtains 1 22 degree of incident angles (in air), the worst case position angle contrast ratio of 000: 1.This is reduced to 400: 1 the incident angle of 30 degree.About spinner state, the worst case position angle contrast ratio of 1,000: 1 is approximately 20 degree, and at 30 degree, contrast ratio is 250: 1.Although so there are six layers of uniaxial retardation sheet lamination, overall performance is a bit similar.

High-contrast is expected in wider visual field, exist and propose high performance selection.Under parallel polarizer closes closed state, it is common that the geometry of axle rotates two polarizers, and if lamination keeps vertical incidence polarisation transformation, then can keep contrast.By constructing the lamination (getting Nz=0.5) of (such as, as what manufactured by the company of such as Nitto-Denko, Corp.) biaxial retarder film, obtain the polar plot shown in Figure 18.In this case, this map combining reaches the scope of 80 degree of half-angles, and contrast ratio is better.The incident angle of 60 degree, worst case position angle contrast ratio is 4,760: 1.

In order to the problem making the geometry being in crossed-polarizer pass closed state rotate is minimum, multi-form compensation can be used.Such a embodiment is, along transmission axle, twin shaft half-wave retardation sheet (same, to get Nz=0.5) is laminated to input polarization device.Half-wave retardation sheet is substantially inoperative for any incident angle in 0/90 degree of position angle when vertical incidence.But at other position angles, optical axis keeps stable, the optical axis experience geometry of polarizer rotates simultaneously.For being redirected to by input polarization, to settle along the absorption axle of analyzer be desirable in the reflection of polarization be associated with half-wave retardation sheet.In embodiments, each eyeglass should comprise additional compensator.

As previously mentioned, the two condition polarization switch of present disclosure can also for generation of other forms of modulation.The two condition of linear polarization switches the otherwise two condition making it possible to use polarization sensitive components below to carry out light beam and switches.By connecting polarization separator (such as, Wollaston prism or grating polarization separation vessel) in described equipment, two condition optical beam redirector can be realized.By connecting polarization selectivity spectral filter (such as, the color polarizer as manufactured by Polatechno or ColorLink) in described equipment, changeable optical filtering can be realized.By connecting light beam dislocation (beam-displacing) prism (or walking from (walk-off) prism) in described equipment, the binary shift of light beam or image can be realized.

In addition, two condition polarization switches in metrology and diagnostics and has many application.This comprises target and is to use sequential grammar to carry out the application of the polarization state of analyzing input beam, such as polarimetry.This can also comprise diagnostic application, such as optical coherence tomography.

Although be described above the various embodiments according to disclosed principle, should be appreciated that, they only exemplarily provide, and nonrestrictive.Therefore, the range of the present invention (one or more) and scope should not limit by any one in above-mentioned exemplary, but should only according to present disclosure announce claim and equivalents limit.In addition, above advantage and feature provide in the embodiment described in which, but the application of the claim announced like this should be limited to and realize any one or whole process in above advantage and structure.

As spendable herein, the tolerance limit that the relativity between the term that term " substantially " and " approximately " they are its correspondence and/or project provides industry generally acknowledged.The scope of the tolerance limit that such industry is generally acknowledged from being less than one of percentage to 10, and corresponds to, but is not limited to, component value, angle, etc.The scope of the relativity between such project be less than one of percentage to 10 between.As spendable herein, term " substantially insignificant " refers to very little relative difference, the scope of described very little relative difference be less than one of percentage to 10 between.

In addition, provide chapter title to be herein in order to consistent with the suggestion of 37C.F.R.1.77, or otherwise be for providing organizational cues.These titles should not limit or characterize the invention (one or more) of setting forth any claim can announced from present disclosure.Specifically, exemplarily, although title refers to " technical field ", such claim should be restricted to by language selected under this title and describe so-called technical field.Further, the description of the technology in " background technology " should not be read as admits that this technology is the prior art of any invention (one or more) in present disclosure." summary of the invention " should not be considered to be in the sign of the invention (one or more) of setting forth in disclosed claim yet.In addition, should not be used to prove only there is a novel point in this disclosure to any discussion of " invention " of odd number in present disclosure.Can set forth multiple invention according to the restriction of the multiple claims announced from present disclosure, and these claims correspondingly define the one or more invention and their equivalents protected thus.In all examples, the scope of such claim is understood according to the essence of present disclosure according to these claims itself, and should not limited by title described in this paper.

Claims (26)

1. a light polarization modulator, described light polarization modulator can operate and carry out time-modulation to the linearly polarized light injected in light path, and described light polarization modulator comprises:

Polarization is taken turns, and described polarization wheel is positioned in the light path of described linearly polarized light, and described polarization wheel has the first circular arc district and the second circular arc district,

At least one in wherein said first circular arc district and described second circular arc district comprises the multilayer retardation plate lamination light filter with multiple linear delay sheet.

2. light polarization modulator as claimed in claim 1, wherein said retardation plate lamination light filter has insignificant delay substantially.

3. light polarization modulator as claimed in claim 1, wherein said retardation plate lamination light filter has circular base vector.

4. light polarization modulator as claimed in claim 1, wherein regardless of the angle position of described polarization wheel, described retardation plate lamination light filter all makes described linearly polarized light rotate predetermined angular.

5. light polarization modulator as claimed in claim 1, wherein said retardation plate lamination light filter has substantially invariable phase differential in visible light between dextropolarization and left-hand polarization.

6. light polarization modulator according to claim 1, wherein said first circular arc district comprises the first retardation plate lamination light filter, and described second circular arc district comprises the second retardation plate lamination light filter.

7. light polarization modulator as claimed in claim 6:

Wherein regardless of the angle position in described first circular arc district, described first retardation plate lamination light filter all makes described linearly polarized light rotate the first predetermined angular when being irradiated by described linearly polarized light,

Wherein regardless of the angle position in described second circular arc district, described second retardation plate lamination light filter all makes described linearly polarized light rotate the second predetermined angular when being irradiated by described linearly polarized light,

Wherein said first predetermined angular is orthogonal with described second predetermined angular.

8. light polarization modulator as claimed in claim 6:

Wherein said first retardation plate lamination light filter is θ degree polarization state spinner, and

Wherein said second retardation plate lamination light filter is (θ-90) degree polarization state spinner.

9. light polarization modulator as claimed in claim 8:

Wherein said first retardation plate lamination light filter is+45 degree polarization state spinners, and

Wherein said second retardation plate lamination light filter is-45 degree polarization state spinners.

10. light polarization modulator as claimed in claim 1, the polarisation of light state wherein left in the light path in described first circular arc district is orthogonal with the polarisation of light state in the light path leaving described second circular arc district.

11. light polarization modulators as claimed in claim 1, each half providing described polarization to take turns in wherein said first circular arc district and described second circular arc district.

12. light polarization modulators as claimed in claim 1, wherein said first circular arc district is by input polarization polarisation of light state conversion 90 degree, and described second circular arc district does not convert described input polarization polarisation of light state.

13. light polarization modulators as claimed in claim 2, wherein said first circular arc district and each of described second circular arc district comprise dispersionless retardation plate material substantially.

14. light polarization modulators as claimed in claim 13, wherein said dispersionless retardation plate material substantially comprises one of cyclic olefine copolymer (COC) and polycarbonate.

15. light polarization modulators as claimed in claim 1, also be included in the quarter-wave retardation plate in described polarization wheel light path below, described quarter-wave retardation plate is oriented and becomes+45 degree relative to the polarization state from described first circular arc district, and is oriented relative to polarization state one-tenth-45 degree from described second circular arc district.

16. light polarization modulators as claimed in claim 1, wherein said retardation plate lamination light filter comprises finite impulse response (FIR) (FIR) light filter, and can operate the light pulse producing at least N+1 spatial deviation in response to linearly polarized light Puled input.

17. light polarization modulators as claimed in claim 1, wherein said polarization wheel also comprises antireflective coating.

18. 1 kinds of stereo projection systems, described stereo projection system comprises:

Projector sub-system; And

Light polarization modulator subsystem,

Projected image time-modulation from described projector sub-system is orthogonal polarisation state by described light polarization modulator subsystem operable,

Wherein said light polarization modulator subsystem comprises:

Polarization is taken turns, described polarization wheel has the first circular arc district and the second circular arc district, wherein said first circular arc district comprises the first multilayer retardation plate lamination light filter with first group of multiple linear delay sheet, and wherein said second circular arc district comprises the second multilayer retardation plate lamination light filter with second group of multiple linear delay sheet.

19. stereo projection systems as claimed in claim 18, also comprise controller, and described controller is suitable for synchronously controlling with the projected image from described projector sub-system the position that described polarization is taken turns.

20. stereo projection systems as claimed in claim 18, wherein in the light path of linear polarizer between described projector sub-system and described light polarization modulator subsystem.

21. stereo projection systems as claimed in claim 18:

Wherein said first multilayer retardation plate lamination light filter is θ degree polarization state spinner, and

Wherein said second multilayer retardation plate lamination light filter is (θ-90) degree polarization state spinner.

22. stereo projection systems as claimed in claim 21:

Wherein said first multilayer retardation plate lamination light filter is+45 degree polarization state spinners, and

Wherein said second multilayer retardation plate lamination light filter is-45 degree polarization state spinners.

23. stereo projection systems as claimed in claim 18, wherein projecting lens is arranged in described polarization wheel light path below.

24. stereo projection systems as claimed in claim 18, wherein in the light path of projecting lens between described projection subsystem and described light polarization modulator subsystem.

25. stereo projection systems as claimed in claim 18, also be included in the quarter-wave retardation plate in described polarization wheel light path below, described quarter-wave retardation plate is oriented and becomes+45 degree relative to the polarization state from described first circular arc district, and is oriented relative to polarization state one-tenth-45 degree from described second circular arc district.

26. stereo projection systems as claimed in claim 18, wherein said first multilayer retardation plate lamination light filter comprises finite impulse response (FIR) (FIR) optical filter, and can operate the light pulse producing at least N+1 spatial deviation in response to linearly polarized light Puled input.